Fuse and circuit tester.



L. 0. JOHNSON. FUSE AND CIRCUIT TESTER. APPLI'CATION FILED APR. TLIQYHL I/VVE/VTOR ldmkwa/z AWORIVEYS Patented Dec. 11, 19 17..

I WITNESSES. I

LYNN DUANE JOHNSON, OF PORTLAND, OREGON.

FUSE AND CIRCUIT TESTER.

eadees.

Specification of Letters Patent.

iatented Dec. ill, 19m;

Applicationfiled April 7, 1916. Serial No. 88,546.

. simple, safe and reliable device for testing fuse plugs while in circuit with respect to all voltages within any ordinary range.

Among the objects of the invention is to provide a device pf this nature that is practically' fool-proof, since with this device there is no danger, such-as is incident to a device having a common lamp in an open socket, when, by mistake, a low voltage lamp is used upon a high voltage circuit, causing the lamp to blow up and causing a probable injury due to burning or the flying of glass. The device proposed herein is one in which the terminals are always in series with a coil having a known resistance and a lamp is employed for the maximum high voltage, say, for instance, 606, means being provided to test for any desired lower voltage by varying the effect of the resistance coil.

Another object of the invention is to provide a device of this nature which constitutcs a handy tool or implement for the electricians kit, the device being very small and portable and adapted for use by any electrician or engineer in connection with any works where there is any considerable amount of electricity consumed for light or power. j

A further use for the device is by janitors or super ntendents of apartment houses or similar buildings for locating blown fuses whereby numerous emergency calls might be eliminated if the person'in charge, with a slight knowledge of electricity, is enabled to locate the trouble.

With the foregoing and other objects in view, .the invention consists in the arrangement and combination of parts hereinafter described and claimed, and while the invention is not restricted to th exact details of construction disclosed her .in, still for the purpose of illustrating a practical embodiment thereof reference is had to the accom panying drawings, in which like clzaractors of reference designate the same parts in the several views, and in which I Figure 1 is a perspective View of the appliance complete as it would be carried in ones kit;

Fig. 2 is a plan view of the device with the face plate removed; and

Fig. 3 is a diagram indicating the principal electrical parts.

Referring now more particularly to the drawings, 1 show a casing 10 of rectangular construction into one end 11 of which are projected a pair of fixed, flexible, insulated contact terminals 12 and 13 constitutin fixed parts of the apparatus.

The terminal 12 includes a wire 12 which leads into the interior of the casing where it connected at let to the metallic contact against which the end 15 of a pilot lamp 16 projects. The base 17 of the lamp is fitted in a clamp 18 from which'an insulated wire l leads through a partition 20, separating the interior of the casing into two main parts, to a resistance coil 21 of known high resistance.

While the lamp 16 occupies the major portion of one half of the casing, the coil 21 is fitted snugly in the other half of the casing, occupying approximately two-thirds thereof, but having its upper end spaced from the end 11 of the casing. The coil is locked in positionby a. vertical bridge 22 of insulation lying inthe vertical and longitudinal axis of the coil, The bridge is held positively from lateral displacement by being fitted between pairs of blocks or shoulders connected to the end 11 and end of the .coil, spool respectively, and therefore it serves to hold the coil from endwise'movemcnt.

This bridge 22 carries a plurality of spaced contacts 23, 24 and 25. The contact 23 is connected by a Wire 26 to the end of the resistance coil remote from the connection 19. 'Thecontact 24 has direct connect-ion with the wire 13 of the outside terminal 13, and a spring contact 27 is likewise connected to the contact 24 and has normal connection at its free end with the con tact 23.

A pushabutton 28 projects through one side of the casing and engages at its inner end againstthe spring 27, said spring servmg to hold the push button projected outlmver.

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